Type 4 2.0L AMC cylinder heads

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cjacaruso
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Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Sat Apr 03, 2021 7:10 pm

So I have put on a pair of new AMC heads on my type 4 2.0L engine. As I am assembling I am having a lot of trouble getting the engine tin to fit and the intake manifolds to go on. When comparing the AMC to my old cracked VW heads I notice the outside castings are a bit different than the VW heads. This seems to be the reason for the trouble fitting the tin and intake manifolds. Has anyone else had this problem? I can use a Dremel to remove some of the excess aluminum casting material. I can force the sheet metal and intake manifolds on if necessary but I would prefer to get the fit better. Any info will help. Thanks!

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Re: Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Sun Apr 04, 2021 5:00 pm

I ground away some extra aluminum flashing from the AMC heads just above the valve covers and just below the intake area. Now the intake manifolds fit nicely. The AMC's had some extra flashing/casting which sat about 1/4" higher than the original VW heads. I'm still trying to figure out how to get the tins to fit better. Both main tins which fit over the cylinders and heads hit the heads which prevents them from seating all the way down. The AMC heads are about 2 mm (42.5 vs 40.5) wider than the VW heads across the fin area closest to the case. I don't want to take too much off of the last fin but would also like the tins to fit correctly. They are original VW tins. Each fin is about 3.5 mm so if I take off 2 mm..... Maybe I'm being too picky and should just put 'em on and call it good enough.

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satchmo
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Re: Type 4 2.0L AMC cylinder heads

Post by satchmo » Mon Apr 05, 2021 7:08 pm

You won't hurt anything by grinding away a bit of the cooling fins.

The new AMC heads should have any extraneous casting flashing ground down anywhere you can reach it.

Satchmo
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Re: Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Thu Apr 08, 2021 7:23 pm

Thanks Satchmo! Kind of what I thought. I wish I would have looked more carefully before bolting up the cylinder heads to the cylinders. I'll get there.

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satchmo
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Re: Type 4 2.0L AMC cylinder heads

Post by satchmo » Thu Apr 08, 2021 9:45 pm

Haha, yes, we’ll all get there.
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Re: Type 4 2.0L AMC cylinder heads

Post by RandyM » Wed May 26, 2021 6:02 pm

I bought the Bus Depot AVP 2.0 type IV engine with new AMC heads. I'm still in the break in period. I have a Dakota Digital CHT under #3 plug. Engine was professionally installed with all tin and thermostat. Oil pressure is normal, oil temp is always below 200 BUT CHT seems to run hot. 400 +/-, and 450-460 on occasion (hill, long runs at 60mph). Several mechanics here with long creds say everything is spot on, and one says AMC heads are Vanagon type and run hot like that.

What say you all?

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satchmo
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Re: Type 4 2.0L AMC cylinder heads

Post by satchmo » Thu May 27, 2021 8:42 am

450-460 seems really hot, and, if the engine seems to be running well in every other regard, I would suspect the accuracy of your gauge reading (Note that I said gauge reading and not gauge. Dakota Digital gauges have a very good reputation).

The first, and easiest, step to address this would be to get another measurement of the head temperature via another modality, like a laser thermometer. With the tins in place you would need to find an area near the exhaust manifold to get your reading.

A second check would be to pull the spark plugs and look at the electrode tips. If they are a medium to light brown, then you know your CHT temps are good, and the gauge reading is off.

I have heard that many folks have trouble with the ring terminal CHT sensor not sealing well, which leads to anomalous readings (too hot). There isn't much room in the spark plug well for the required 90 degree bend of the ring terminal, which causes the ring terminal to deform during installation. Failure to remove the original spark plug sealing ring before installing the CHT sensor will also cause problems with sealing, so make sure that was done.

Good luck, Satchmo

PS: I call BS on the mechanic who says "AMC heads are Vanagon type and run hot like that."
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Amskeptic
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Re: Type 4 2.0L AMC cylinder heads

Post by Amskeptic » Wed Jun 16, 2021 5:12 pm

" I call BS on the mechanic who says 'AMC heads are Vanagon type and run hot like that.'"

Ah yes, the famous feint, the escape, the sheer irresponsibility.

AMC heads are *especially sensitive* to heat, and must be kept at *cooler* temps than the factory heads due to a softer alloy that does reduce cracks but suffers from distortions in the combustion chamber ceilings/rocker supports above.

AMC needs to be run no more than 400* consistently. Brief hillclimbs at 420* sure, but check your valves frequently as the heads take a set. It took mine almost 20,000 miles to settle.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 206,865 miles
Naranja - 77 Westy . . . 132,040 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

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Re: Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Sat Jul 10, 2021 5:25 pm

Thanks for all the info on the AMC's. Miraculously, the engine finally starts! It runs horribly and the tranny barely works. I've rebuilt a few of these air cooled engines type 1 and type 4 but this is by far the most difficult. I'm kind of feeling that there is just a lot of really bad parts out there. I'm noticing rubber parts I replaced last year are already cracked with zero miles. Engine is acting like it has a vacuum leak or maybe timing is out of whack. I had a terrible time getting the distributor in and timed. Timed correctly there is major interference with the cold start valve. I don't ever recall this before as an issue. I tried rotating the distributor drive gear one tooth from recommended and then good distributor clearance but no start. I guess the distributor drive gear really needs to be set 12 degrees. Regarding the tranny, it was professionally rebuilt and was working fine when taken for rebuild at 305,000 miles. Thought it would be good to get a rebuild before catastrophic failure. Just can't get the thing to shift smoothly into 2nd gear no matter what I do with the shift plate adjustment under the stick shift. I notice the 2 year old rear shift coupler is very loose so maybe another poor quality part. Anyone know of any place to get a decent rear coupler and better quality rubber parts. I've been getting stuff through Wolfsburg West, Bus Depot, German Supply, CIPI, Go Westy, Busted Bus, J Bugs.

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Re: Type 4 2.0L AMC cylinder heads

Post by Amskeptic » Sun Jul 11, 2021 6:24 pm

cjacaruso wrote:
Sat Jul 10, 2021 5:25 pm
Thanks for all the info on the AMC's. Miraculously, the engine finally starts! It runs horribly and the tranny barely works. I've rebuilt a few of these air cooled engines type 1 and type 4 but this is by far the most difficult. I'm kind of feeling that there is just a lot of really bad parts out there. I'm noticing rubber parts I replaced last year are already cracked with zero miles. Engine is acting like it has a vacuum leak or maybe timing is out of whack. I had a terrible time getting the distributor in and timed. Timed correctly there is major interference with the cold start valve. I don't ever recall this before as an issue. I tried rotating the distributor drive gear one tooth from recommended and then good distributor clearance but no start. I guess the distributor drive gear really needs to be set 12 degrees. Regarding the tranny, it was professionally rebuilt and was working fine when taken for rebuild at 305,000 miles. Thought it would be good to get a rebuild before catastrophic failure. Just can't get the thing to shift smoothly into 2nd gear no matter what I do with the shift plate adjustment under the stick shift. I notice the 2 year old rear shift coupler is very loose so maybe another poor quality part. Anyone know of any place to get a decent rear coupler and better quality rubber parts. I've been getting stuff through Wolfsburg West, Bus Depot, German Supply, CIPI, Go Westy, Busted Bus, J Bugs.
Well hell's bells, you seem to have the perseverence, now you need the results.

Just a few questions:

a) 12* once seated. It rotates as it engages the brass gear. Is the distributor an original? (205p, IIRC)

b) out of whack timing does not make the engine run poorly, but it can make the engine fel sluggish or run hot

c) do you implicitly trust your timing scale and notch on the pulley? 28* max at 3,400 rpm no hoses.

d) if you had trouble at the intake manifolds/cylinder tins, check gaskets carefully for leaks with WD-40 on a slightly warmed-but-not-hot engine, see if idle changes when you spray each manifold

e) fuel injector seals all good?

f) certifiably good elbow at the AAR?

g) replacement AFM? Check mixture for dreadful lean after insuring that there are no intake leaks.

h) snug up rear coupler if you can, spring-loaded shifters need a relaxed stop plate adjustment
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 206,865 miles
Naranja - 77 Westy . . . 132,040 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

cjacaruso
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Re: Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Sun Jul 11, 2021 10:03 pm

a) Distributor is an original. High miles. I have a spare also an original. At some point I am thinking about having one of them rebuilt. I'm not sure how to test to make sure they are working correctly.

b) Fixed the timing issue somewhat. I did a static timing to get it running. Set it to 7.5 BTDC. Once I got a decent timing light I checked the timing dynamically and it was @ 40 degrees BTDC at 900 RPM. Wow, so I set it to 7.5 BTDC and runs much better. Still lacks power going uphill. You are suggesting I plug distributor hoses and check timing at 3400 RPM? I hear all kinds of things for timing so I went with the Bentley suggestion for now. I will check this tomorrow.

c). I do trust the scale and notch. I just replaced the plastic scale with a metal one. The notch in the pulley is original and I spent some time painting it to make it stand out once I was confident I had the right notch.

d). I will try this.

e). Fuel injectors were rebuilt and tested by Rich at Cruzin Performance in Michigan. New seals.

f). New elbow at AAR. Old one pretty worn out. I checked today to make sure it was on correctly. It is.

g). AFM is a Bosch. Not the original but an exact replacement purchased 25 years ago. I still have the original which may or may not be good. Know of anyone who tests these? Would be nice to have a legit back up!

h). I did disassemble and reassemble the rear coupler and that seemed to tighten it up.

The good news is that three things are better today than yesterday with regards to this engine and I have a plan to make progress again tomorrow! Thank you!!

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Amskeptic
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Re: Type 4 2.0L AMC cylinder heads

Post by Amskeptic » Mon Jul 12, 2021 1:21 pm

cjacaruso wrote:
Sun Jul 11, 2021 10:03 pm
b) Fixed the timing issue somewhat. I did a static timing to get it running. Set it to 7.5 BTDC. Once I got a decent timing light I checked the timing dynamically and it was @ 40 degrees BTDC at 900 RPM. Wow, so I set it to 7.5 BTDC and runs much better. Still lacks power going uphill. You are suggesting I plug distributor hoses and check timing at 3400 RPM? I hear all kinds of things for timing so I went with the Bentley suggestion for now. I will check this tomorrow.
That is utterly odd to have such an enormous discrepancy between static and dynamic timing. Does your timing light have a dial? Make sure it is zeroed out. We don't care about idle timing. Your engine *works* at the higher rpm specified, and that is where we must be correct. Even 3* too advanced increases heat appreciably. No greater than 28* BTDC, and then make sure the vacuum advance is getting it up to 38*-40* when you put the hose back on.

cjacaruso wrote:
Sun Jul 11, 2021 10:03 pm
c). I do trust the scale and notch. I just replaced the plastic scale with a metal one. The notch in the pulley is original and I spent some time painting it to make it stand out once I was confident I had the right notch.
Don't *trust* the metal scale. Aftermarket is notorious. If you have an original scale, with the ends absolutely not twisted at the top (properly horizontal) and not twisted at the bottom either, set the crank to "0". Then install the aftermarket scale and see if things align. If not, do whatever simple math is required to hit 28* i.e. metal scale reads 2* ATDC then adjust 3,400 rpm to 26* BTDC.

cjacaruso wrote:
Sun Jul 11, 2021 10:03 pm
I have a plan to make progress again tomorrow! Thank you!!

and tomorrow and tomorrow and tomorrow and tomor.....
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 206,865 miles
Naranja - 77 Westy . . . 132,040 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

cjacaruso
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Re: Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Mon Jul 12, 2021 8:30 pm

Yes the discrepancy between static and dynamic is something I've never encountered before. Usually the static timing gets things close enough to run OK if not ideal. The good news is that I no longer have an interference issue with the distributor can hitting against the CSV plug! I don't think my timing light has a zero out adjustment. I just got it so I will check for that.

Regarding the metal scale, I will check as you have explained. I do still have the original but it is kind of worn out, but usable for testing purposes.

Thank you. Again!!

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Re: Type 4 2.0L AMC cylinder heads

Post by airkooledchris » Fri Jul 16, 2021 8:12 pm

RandyM wrote:
Wed May 26, 2021 6:02 pm
I bought the Bus Depot AVP 2.0 type IV engine with new AMC heads. I'm still in the break in period. I have a Dakota Digital CHT under #3 plug. Engine was professionally installed with all tin and thermostat. Oil pressure is normal, oil temp is always below 200 BUT CHT seems to run hot. 400 +/-, and 450-460 on occasion (hill, long runs at 60mph). Several mechanics here with long creds say everything is spot on, and one says AMC heads are Vanagon type and run hot like that.

What say you all?

The AVP engine I had was about the same. No matter what I threw at that setup, it was never happy. That was with rebuilt heads, sucks it's still a thing for them with new heads to.
1979 California Transporter

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